Multiphysics modelling of railway vehicle equipped with...

1

GraSMech – Multibody 1

Computer-aided analysis of multibody dynamics (part 2)

Multiphysics modelling of railway vehicle equipped with pneumatic suspension

Nicolas Docquier([email protected])


Contents

Railway vehicle descriptionClassical railway vehicleSecondary pneumatic suspension

Modelling and numerical methodsMultibodyPneumaticCo-simulation

ApplicationDelta Q/QCurve entry


Contents




2


Railway vehicles

Principle partsCarbody

Running gearRigid-frame vehicles

Bogie vehicles


Conventional bogie

Main components

Bolster

Bogie frame

Wheelset Axle box

Primarysuspension

Secondary suspension


Conventional bogie

Main components

Anti-roll bar

Bolster

Bogie frame

Wheelset Axle box

Primarysuspension


3


Conventional bogie

Main components

Traction rod

Anti-roll bar

Bolster

Bogie frame

Wheelset Axle box

Primarysuspension



Variant of the conventional bogie

Conventional bogie – Jakob’s bogie

Tyred bogieIndependant wheels bogie


Pneumatic circuit

Pneumatic bellow

Stiffness:

Effective area: Ae = 0.1 … 0.4 m2

Volume: V0 = 10 … 40 l

Static load: 50 … 130 kNpressure: p0 = 4 … 8 bar

20

0

eA pkV

≈

4


Pneumatic circuit

Auxiliary tank

VR = 20…100 l

volume stiffness2

0

0

e

r

A pkV V

≈+


Pneumatic circuit

Pipe orifice

pressure drop pneumatic damping


Pneumatic circuit

Levelling valve

5


Pneumatic circuit

Levelling valve

load carbody heightair admission


Pneumatic circuit

Levelling valve

load carbody heightair exhaust


Pneumatic circuit

Levelling valve

neutral position

admission

Air flow

Lever position

pb1

pb2<pb1

exhaust

6


Pneumatic circuit

Safety valve

carbody heightsudden air exhaust

Air flow

Lever position


Pneumatic circuit

Differential pressure valve

Air flow

(pr-pl)


Pneumatic circuit configurations

4 point suspension

2 point suspension

7


Suspension classification

Bogie

Levelling

Anti-roll bar

Auxiliary tank

Conventional Jakob’s bogie

2 points 4 points

With Without

With Without


Contents





Multibody modelling

Carbody modelling6 dofTorsion

2 rigid bodies1 revolute spring

Bogie modelling4 bodies

BolsterFrame2 wheelset

Wheel/rail contact constraint

8


Multibody modelling

SimpackRelative coordinate as RobotranJoint library


Multibody modelling

SimpackRelative coordinate as RobotranJoint library


Multibody modelling

SimpackDedicated railway interface

9


Multibody modelling

SimpackDedicated railway interface


Pneumatic modelling

Pneumatic circuit


Valve modelling

Flow

(pd-pg)

admission

Flow

Lever position

pb1

pb2<pb1

exhaust

Differential valve Levelling valve Exhaust valve

q = f (pbellow, lever pos) q = f (pbellow, lever pos)

q = f (pd, pg)

Flow

Lever position

10


Bellow-tank subsystem

Simpack approachEquation of motion of the pipe

Volume variation in the bellow and tank

Air flow approachBellow

Tank

Pipe

( )c tb c cc

p Rq T p VVγ

= − &&

r tbr

p Rq TVγ

= −&

Vp csteM

γ⎛ ⎞ =⎜ ⎟⎝ ⎠

Mass Volume

( ) 02 rc

2 =−++ ttt

t AppyAym &&& ξρ

( ),rc r c rcq f p p q= −& ( )rc r cq f p p= −differential equation algebraic equation



Model comparisonSinusoidal excitation

z(t) = zmax sin (2π f t)

Reaction force F = (pc-pa)Ae

-5 0 5

x 10-3

3.6

3.8

4

4.2

4.4

4.6x 10

4

z [m]

F [N

]

0 0.2 0.4 0.6 0.8 13.6

3.8

4

4.2

4.4

4.6x 10

4

Time [s]

Forc

e [N

]



Frequencial analysisDynamic stiffness Damping

Simpack

Différential

Algebraic

0 5 10 15 20 25 302

4

6

8

10

12x 105

Frequency [Hz]

Stif

fnes

s[N

/m]

0 5 10 15 20 25 300

0.5

1

1.5

2

2.5

3

Frequency [Hz]

Dam

ping

[-]

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Numerical method

Multibody

PneumaticSimulink

Simpack

Hybrid system


Numerical method

Co-Simulation2 process integrated in parallel

Interaction at fixed time step

Simpack( )

Matlab-Simulink( )

MultibodyModel

PneumaticModel

z, z, L&F


Contents




12


Main characteristics

No anti-roll bar

4 point suspension

Auxiliary tank in the bolster

No pipe between the bellow and the tankalgebraic model for the orifice

Pressure source connected to the auxiliary tank

Actual vehicle analysis


Description of the testStationary vehicleWedges placed under some wheels

Experimental observationsCarbody oscillations

Overloaded bellows:Air admission through levelling valves

Unloaded bellows : Air exhaust through levelling valvesAir exhaust through safety valves

Differential valves engaged

Essai DeltaQ/Q

Bad comfort

62 mm


DeltaQ/Q test

Reference configuration

No equilibrium

Exhaust valve engagedbeginning of oscillations

Air admission on one side,air exhaust on the other side

0 10 20 30 40

-20

0

20

40

Time [s]

Dis

plac

emen

t [m

m]

Rear left

0 10 20 30 40

-20

0

20

40

Time [s]

Rear right

0 10 20 30 40

-20

0

20

40Front right

0 10 20 30 40

-20

0

20

40

Dis

plac

emen

t [m

m]

Front left

13


0 20 40 60

-20

0

20

40Rear right

Time [s]0 20 40 60

-20

0

20

40Rear left

Time [s]

Dis

plac

emen

t [m

m]

0 20 40 60

-20

0

20

40Front right

0 20 40 60

-20

0

20

40Front left

Dép

lace

men

t [m

m]

DeltaQ/Q test

Smaller pipe orificeLarge oscillations avoided

Safety valve engaged after 50s no equilibrium

0 10 20 30 40 50 60 70-30

-20

-10

0

10

20

30

40Rear right

Time [s]

Disp

lace

men

t [m

m]


|pga-pdr| < 2.25 bar

DeltaQ/Q test

Differential valve modificationpga-pdr > 2.25 bar

pga pdr pga pdr

pa

0 20 40 60 80 100-30

-20

-10

0

10

20

30

40

Time [s]

Disp

lace

men

t [m

m]

Rear right

airflow between auxilary tanks air exhaust to atmosphere


0 20 40 60 80-2

-1.5

-1

-0.5

0

Time [s]

Rol

l ang

le [°

]

Curve entry

Full loadEmpty carbody

Curve radius 100 mInitial speed 10 m/s

lateral accelertation 1 m/s²

0 20 40 60 80-2

-1.5

-1

-0.5

0

Time [s]

Rol

l ang

le [°

]

All valves connectedSafety valve disconnectedLevelling valve and safety valve disconnected

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Conclusion

Pneumatic modellingModel of the bellow-tankModel of the complete circuit (valves…)

Study of an actual vehicle systemAnalysis of an experimental problemSolution proposal investigation

Future work1D model of the pipe Better description of the valvesComparison of the various pneumatic circuit configurations

Multiphysics modelling of railway vehicle equipped with...

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